Valve mechanism for multiple distributor fluid treatment system

ABSTRACT

A valve mechanism is used in combination with a fluid treatment device of the type having a tank defining a treatment bed, particulate treatment material contained within the treatment bed, and a central distribution tube mounted in the bed and terminating in a plurality of distributors which provide fluid communication between the bed and the distribution tube. The valve mechanism consists of a plurality of ball valves, each connected to a different one of the distributors and having unidirectional flow restriction assemblies such that fluid flow in a first direction from the bed to the distributor tube is relatively unrestricted, and fluid flow in a second direction from the distribution tube to the treatment bed is relatively restricted. By providing a substantial flow restriction resistance in each of the distributors conduits, fluid flow through the distributors during a backwashing cycle remains relatively balanced regardless of the variation in resistance due to dirt concentration around each distributor so that the treatment material surrounding each distributor is sufficiently agitated.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to fluid treatment systems, and moreparticularly, to water treatment systems utilizing a bed of particulatetreatment material and having apparatus for regenerating the treatmentmaterial.

2. Prior Art

Many large, commercial water treatment systems of the ion exchange typepresently in use are constructed to receive untreated water through aninlet line in the top of a pressure tank so that it percolatesdownwardly through a bed of treatment material, such as zeolite, andpasses out of the pressure tank through an outlet line originating in alower portion of the tank. The outlet line preferably consists of acentral distribution tube, mounted within the pressure tank, and aplurality of distributor conduits extending outwardly from a lower endof the central distribution tube and terminating in distributors. Thedistributors are generally hollow and cylindrical in shape, and haveperforations in their walls to permit the entry of water from thepressure tank while preventing the entry of the treatment material. Asthe untreated water percolates through the bed of treatment material, anion exchange takes place in which ions held by the treatment materialare exchanged for ions in the untreated water. It is important that theflow resistance provided by the overall system during normal operationbe kept to a minimum so that the pressure of the treated water does notdrop below a minimum pressure level.

The water treating ability of the treatment bed is gradually reduced bycontinued use and, after a predetermined quantity of water has beentreated, the treatment material in the bed becomes depleted and is nolonger able to effect an ion exchange. The treatment bed is thereafterregenerated by passing a fluid solution through it so that the ionexchange process is reversed: the ions held by the spent treatmentmaterial which had been received from the water are exchanged for ionssuspended in the regenerating fluid solution.

Prior to the regeneration cycle of a typical water softening system, thesystem undergoes a backwashing cycle in which water, which may be hard,soft, or decationized, enters the pressure tank through the centraldistribution tube and exits the distributors to percolate upward andleave the pressure tank through the inlet line. This flow of water fromthe distributors upwardly causes the treatment material to be agitated,which loosens the packed treatment material and forces deposits ofdebris previously carried into the pressure tank from the inlet line tomigrate upwardly through the treatment bed and out the inlet line. Theloosened material can be regenerated more thoroughly.

To provide a thorough removal of accumulated debris from the treatmentbed during this backwashing cycle, it is important that the entire resinbed be agitated. However, if the distributors are placed at differentlevels within the pressure tank, or where debris has accumulated to agreater degree around one or more of the distributors than around theremaining distributors, the resistance to fluid flow from the centraldistribution tube through the distributors becomes unequal. As a result,fluid flow through the distributors from the central distribution tubeis unequal, as the water follows the path of least resistance. Sincefluid flow through those distributors having the greatest resistance isthe least, the treatment material surrounrding those distributors isagitated less than the treatment material around the other distributorshaving relatively little resistance. Consequently, accumulated debris isnot removed as thoroughly from the treatment material having heaviersoil concentrations as it is from treatment material having lighterconcentrations of soil.

Accordingly, there is a need for a water treatment system whichcompensates for the variance in resistance to fluid flow through thedistributors during a backwash cycle so that the fluid flow through eachdistributor is not reduced substantially as a result of debrisconcentration, whereby all portions of the treatment bed may be agitatedsufficiently.

SUMMARY OF THE INVENTION

The present invention provides an improved water treatment system of thetype having a plurality of distribution conduits extending from acentral distribution tube and terminating in distributors. Theimprovement consists of the addition of a valve mechanism which permitsbalanced flow of fluid from the central distribution tube through thedistributors and into the treatment bed of the pressure tank, therebycompensating for variations in resistance surrounding each distributorand caused by soil debris conditions and/or the variation in elevationwithin the pressure tank of the distributor, during the backwashingcycle. Although the invention will be described in reference to a watersoftening system, the invention will function effectively in any gaseousor liquid fluid treatment system having a bed of treatment material anda multiple distributor apparatus for agitating the treatment materialduring a backwashing cycle.

The valve mechanism of the invention preferably consists of a pluralityof ball valves, each mounted on a different one of the distributionconduits and having a unidirectional flow restriction component orietedsuch that fluid flow in a first direction from the bed through thedistribution conduit to the central distribution tube is relativelyunrestricted, and fluid flow in a second direction from the centraldistribution tube to the treatment bed is relatively restricted. Theball valve preferably consists of a hollow body which defines a chamberhaving an inlet communicating with the central distribution tube and anoutlet communicating with the distributor and treatment bed, a ballpositioned within the chamber, a first ball seat member associated withthe inlet for seating the ball during fluid flow in the first direction,and a second ball seat member associated with the outlet for seating theball during fluid flow in the second direction. The first ball seatmember defines a first opening position to permit a relativelyunrestricted flow of fluid through the inlet when the ball is seated inthe first ball seat member during fluid flow in the first direction. Thesecond ball seat member defines a second opening, smaller than the firstopening, positioned to provide a relatively restricted flow of fluidthrough the outlet when the ball is seated in the second ball seatmember and the fluid is flowing in the second direction.

The effect of the ball valves is to introduce a restriction orresistance into each distribution conduit that is relatively large inmagnitude compared to the variations in resistance anticipated to occurin the treatment bed due to soil debris conditions and/or the relativeelevations of the distributors within the pressure tank. By providing arelatively large resistance in each of the distribution conduits, thetotal resistance for each distribution conduit--which comprises theresistance provided by the ball valve added to the increased resistanceresulting from conditions existing about the associated distributor--will be substantially the same. Therefore, during the backwashingcycle when fluid flows from the central distribution tube through thedistributors to the treatment bed, fluid flow will be substantially thesame through each distribution conduit. Agitation of the treatment bedin order to dislodge collected debris will be substantially the same forthe areas surrounding each distributor, so that the treatment bed isuniformly agitated and thereby thoroughly cleansed.

Accordingly, it is an object of the present invention to provide animproved valve mechanism for a multiple distributor water treatmentsystem which eliminates extreme variations in fluid flow from onedistributor to another during backwashing which would otherwise becaused by variations in debris concentration in the treatment materialsurrounding the distributors and/or the variations in elevation of thedistributors within the treatment bed; and to provide such a valvemechanism which does not significantly affect fluid flow during normaloperation of the water treatment system.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTON OF THE DRAWINGS

FIG. 1 is a fragmentary side elevation in section of a pressure tankshowing the multiple distributor system of the preferred embodiment ofthe invention;

FIG. 2 is a detail of one of the valves of FIG. 1, showing the valvebody in section and the ball seated on the outlet ball seat;

FIG. 3 is a section of the ball valve of FIG. 2 taken at line 3--3;

FIG. 4 is a section of the ball valve of FIG. 2 taken at line 4--4;

FIG. 5 is a perspective view of the ball valve of FIG. 2 and havingarrows showing fluid flow during a backwashing cycle; and

FIG. 6 is a perspective view of the ball valve of FIG. 2, modified toshow the ball seated against the inlet ball seat and having arrowsshowing fluid flow during a water treatment cycle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The multiple distributor water treatment system of the present inventionis shown in FIG. 1. A pressure tank 10 defines a treatment bed 12containing a quantity of particulate treatment materal 14, preferably agranulated resin such as zeolite. The pressure tank 10 is sealed fromthe atmosphere at its top (not shown) in a manner well-known in the artand disclosed, for example, in U.S. Pat. No. 4,289,617, issued to theassignee of the present invention.

Mounted within the pressure tank 10 is a central distribution tube 16which extends downwardly from the top of the tank into the treatment bed12. Central distribution tube 16 communicates with a valve mechanism(not shown) which is capable of placing the tube in fluid communicationwith either a supply line, which in turn communicates with a source ofwater under pressure so that the water flows downwardly through thetube, or with an outlet line (not shown) which conveys water which haspassed through the treatment bed 12 and distribution tube to terminalpoints where the treated water is used.

The central distribution tube 16 terminates in a plurality ofdistribution conduits 18. The distribution conduits each include a valve20 and a distributor 22 (shown in FIG. 2). The distributors 22 aregenerally frusto-conical in shape and have a wall 24 defining aplurality of openings 26 which permit fluid communication between thedistribution conduit 18 and treatment bed 12.

The valves 20 each have a generally cylindrical valve body 28 defining avalve chamber 30 including an inlet 32 and an outlet 34. The inlet 32 ofeach valve 20 communicates with its associated distribution conduit 18,and the outlet 34 communicates with its associated distributor 22. Aball 36 is positioned within the valve chamber 30 and is sized so thatit may be displaced either toward the inlet 32 or toward the outlet 34.The ball 36 is preferably constructed so as to have a specific gravityof one or greater.

As shown in FIGS. 2 and 3, the inlet 32 includes a first ball seat 38which is defined by a plurality of rectangular plates 40 extendingdownwardly from the top portion 42 of the valve body 28 adjacent theinlet and disposed radially about the periphery of the inlet opening 44.The ball 36 is sized such that it may be seated against the ball seat 38so that the surface of the ball is supported by the radially inner edges46 of the plates 40, as shown by the phantom ball 36' in FIG. 2.Adjacent plates 40 also define openings 47 which extend from the valvechamber 30 to the inlet opening 44. Preferably, the combined area ofopenings 47 is at least equal to the cross sectional area of inletopening 44 so that fluid flow is unrestricted by the presence of theball 36 on the ball seat 38.

The outlet 34 includes a second ball seat 48, shown in FIGS. 2 and 4.The second ball seat 48 is formed in a cylindrical boss 50 whichsurrounds the outlet opening 52. Boss 50 includes an open, beveled upperend 54 which is sized to receive the ball 36 so that the ball becomessomewhat wedged into the upper end during downward fluid flow, as shownin FIG. 2. The boss 50 includes restrictive side ports 56 formed in itsside which permit fluid communication between the interior 58 of theboss 50 and the valve chamber 30 when the ball 36 is seated on the upperend 54 of the boss.

The operation of the valve mechanism is shown most clearly in FIGS. 1,5, and 6. During the treatment phase of operation of the water treatmentsystem, water enters the top of the pressure tank 10 and migratesdownwardly through the treatment material 14 to the distributors 22. Asthe water filters downwardly, an ion exchange occurs between the ions inthe water (i.e. cations or anions) and the sodium ions in the treatmentmaterial. For example, in a common water softening process, the metallicions in the water are replaced by sodium or hydrogen ions. By the timethe water has reached the location of the distributors 22 it has becomesubstantially depleted of ions and the treated water then passes throughthe distributors, the distribution conduits 18, and the centraldistribution tube 16 to be conveyed to a location remote from thepressure tank for use. During this phase of operation, the valves 20operate as shown in FIG. 6. The fluid path, shown by the arrows A, is ina generally upward direction from the distributor 22, through the boss50, and into the valve chamber 30. The force of the fluid causes theball 36 to travel upward toward the inlet 32 of the valve body, where itbecomes seated on the first ball seat 38. In this mode, the fluid passesfrom the valve chamber 30 freely through the openings 47 and into thedistribution conduits 18 (FIG. 1). The space defining the openings 47 issufficiently large to allow fluid flow from the valve chamber 30 to thedistribution conduit 18 in each valve 20 without forming a restrictionwhich would reduce the rate of fluid flow through the valve.

When the water treatment system is cycled and is placed in thebackwashing mode, water flow through the pressure tank 10 is reversed sothat water flows in the direction of arrows B in FIGS. 1 and 5. Thus,water enters the pressure tank 10 through the central distribution tube16 and travels through the distribution conduits 18, distributors 20,and into the treatment bed 12 where it travels upwardly and, in doingso, agitates the treatment material 14. As shown in FIG. 5, thedownwardly flowing water enters the valve 20 through the inlet 32,thereby forcing the ball 36 downwardly upon the upper end 54 of thesecond ball seat 48. The diameter of the valve body 28 is such that theball 36 cannot fall between the conduit 50 and the interior wall of thevalve body. Rather, it encounters the beveled upper end 54 of theconduit 50 and falls by gravity and by the force of the flowing fluid toclose the second ball seat 48. Thus, in the backwashing mode ofoperation, the fluid entering the valve chamber 30 through the inlet 32must pass through the restrictive side ports 56 in the boss in order toexit the outlet 34 of the valve.

Thus, during the backwashing mode of operation, the valves 20 createsubstantial restrictions in the distribution conduits 18 resulting in avery large resistance occuring in each of the distribution conduits.Preferably, the magnitude of the resistances created by the valves 20 ismuch greater than any anticipated resistance created by deposits of soildebris surrounding one or more of the distributors 22, or resulting fromdifferences in elevation within the pressure tank 10. As a result, thecombined resistance for each distribution conduit 18, comprising theresistance of the valve 20 added to any resistance caused by thecondition of the treatment material surrounding the distributor, aresubstantially the same for each distributor. Thus, fluid flow throughthe distribution conduits 18 is uniform and the treatment material 14surrounding each distributor 22 is agitated sufficiently to dislodgecollected soil debris therein.

It should be noted that, while the preferred embodiment comprises a ballvalve, any valve which provides unidirectional flow restrictioncharacteristics such that fluid flow in a first direction is relativelyunrestricted, and fluid flow in a second direction opposite the firstdirection is relatively restricted, can be used without departing fromthe scope of the invention. Therefore, it is to be understood that theinvention is not limited to this precise form of apparatus, and thatchanges may be made therein without departing from the scope of theinvention.

What is claimed is:
 1. In a fluid treatment device of the type having atank defining a treatment bed, particulate treatment material containedwithin said treatment bed, and a central distribution tube mounted insaid bed and terminating in a plurality of distribution means, saiddistribution means providing fluid communication between said bed andsaid tube, the improvement wherein each of said distribution meanscomprises:valve means having unidirectional flow restriction means suchthat fluid flow in a first direction from said bed through each of saiddistribution means to said central distribution tube is relativelyunrestricted by said flow restriction means, and fluid flow in a seconddirection from said central distribution tube through each of saiddistribution means to said bed is reduced but not eliminated by saidfluid restricton means.
 2. The treatment device of claim 1 wherein eachof said valve means comprises a ball valve.
 3. The treatment device ofclaim 2 wherein each of said ball valves comprises:a hollow bodydefining a chamber and having an inlet communicating with said centraldistribution tube and an outlet communicating with said bed; a ballpositioned within said chamber such that fluid flow in said firstdirection causes said ball to be displaced toward said inlet, and fluidflow in said second direction causes said ball to be displaced towardsaid outlet; a first ball seat member associated with said inlet forseating said ball during fluid flow in said first direction and defininga first opening positioned to permit a relatively unrestricted flow offluid through said inlet when said ball is seated in said first ballseat member; and a second ball seat member associated with said outletfor seating said ball during fluid flow in said second direction anddefining a second opening, smaller than said first opening, positionedto provide a relatively restricted flow of fluid through said outletwhen said ball is seated in said second ball seat member.
 4. Thetreatment device of claim 3 wherein said first ball seat membercomprises a plurality of plate members radially disposed about saidinlet, each plate member having a radially inner edge for receiving saidball such that said plate members define spaces therebetween comprisingsaid first opening.
 5. The treatment device of claim 3 or 4 wherein saidsecond ball seat member comprises a tubular boss surrounding said outletand extending into said chamber, said boss having an upper opening forreceiving said ball and having at least one port comprising said secondopening.
 6. The treatment device of claim 5 wherein said inlet, firstball seat member, second ball seat member, and outlet are substantiallyaligned along a central axis of said body.
 7. The treatment device ofclaim 3 or 4 wherein said inlet, first ball seat member, second ballseat member, and outlet are substantially aligned along a central axisof said body.